The present invention relates to hydraulic control valves and more particularly to pressure regulator valves.
Hydraulic systems generally having a positive displacement for supplying pressurized fluid to a plurality of control valves. Pressure regulator valves are used to provide controlled pressure levers throughout the system by exhausting excess fluid delivered by the pump. The regulator valves generally operate by providing a controlled valve connection between the main pressure inlet and a controlled pressure outlet and also between the controlled pressure outlet and an exhaust passage.
When a spool type valve is used, the valve overlap; i.e., opening and closing of the passages, can result in pulsations of the pressure level at the controlled outlet passage. As the system pressure and flow requirements increase, the sensitivity of the overlap also increases. With the increased flow requirements, system leakage also becomes a factor as the amount of overlap increases.
To provide accurate flow and pressure coverage throughout the desired range results in considerable expense in manufacturing the regulator valves to the desired accuracy.